1. Field of the Invention
The present invention relates to a method for driving a plasma display panel in a matrix display scheme.
2. Description of Related Art
In recent years, a plasma display panel (hereinafter referred to as the xe2x80x9cPDPxe2x80x9d), an electroluminescent display panel (hereinafter referred to as the xe2x80x9cELDPxe2x80x9d) and so on have been brought into practical use as thin flat display panels of matrix display scheme. The PDP and ELDP have pixel cells, which function as pixels respectively, arranged in the form of a matrix comprised of n rows and m columns. The pixel cells have only two states: xe2x80x9clight emissionxe2x80x9d and xe2x80x9cnon-light emission.xe2x80x9d Therefore, gradation driving based on a subfield method is carried out for a display panel such as the above-mentioned PDP and ELDP to provide a halftone luminance level corresponding to an input video signal.
The subfield method involves converting an input video signal into N-bit pixel data pixel by pixel, and composing one field display period with N subfields each of which corresponds to each of N bit digits. A number of light emissions corresponding to each of the bit digits in the pixel data, is allocated to each of the subfields, respectively. When a bit digit in the N bits is, for example, at logical level xe2x80x9c1,xe2x80x9d light is emitted the number of times allocated as mentioned above in a subfield corresponding to the bit digit. On the other hand, when the bit digit is at logical level xe2x80x9c0,xe2x80x9d no light is emitted in the subfield corresponding to the bit digit. The driving sequence using the subfield method represents a halftone luminance level corresponding to an input video signal by a total number of light emission which is performed in each of the subfields within one field display period.
It is an object of the present invention to provide a display panel driving method which is capable of accomplishing a good intermediate luminance display corresponding to an input video signal for a display panel comprised of a matrix of pixel cells, each of which has only two states of light emission and non-light emission.
The present invention provides a display panel driving method for driving a display panel having a plurality of pixel cells arranged in matrix in accordance with a video signal. In each of a plurality of divisional display periods of a unit display period in the video signal, a pixel data writing process is performed for setting each of the pixel cells to either a light emitting cell or a non-light emitting cell in accordance with pixel data corresponding to the video signal to write the pixel data, and a light emission sustain process is performed for causing only the light emission cells to emit light a number of light emissions allocated thereto corresponding to a weighting factor applied to each of the divisional display periods. A luminance distribution of the video signal is measured every display line on the display panel, and the number of light emissions allocated to the divisional display period every display line is changed in accordance with the luminance distribution.